PTL 1 discloses an entertainment system using a portable terminal device as an operation terminal operated by a user rather than using a controller that exchanges operation information with an entertainment device through communication. In PTL1, operating the entertainment device (console) through wireless LAN (Local Area Network) communication using a portable terminal device is referred to as “Remote Play.” During Remote Play, the console transmits, to the portable terminal device, the same video signal as supplied to a monitor device. The main CPU of the portable terminal device shows, on a display panel, an image based on the video signal received from the console. This ensures that, during Remote Play, the same image as shown on the monitor appears on the display panel of the portable terminal device, and that the user can make an operational input to the console by operating the action keys of the portable terminal device.